学习所用代码

test.c

#include<stdio.h>  

int main(){  
    printf("hello");  
    return 0;  
}  

hello.h

#ifndef _HELLO_H  
#define _HELLO_H  
  
/**  
 *fuction:print hello string.  
 *parm:void  
 *return value:void  
 */  

void say_hello();  
#endif  

hello.c

#include "hello.h"  

void say_hello(){  
    printf("hello!");
}  

main.c

#include<stdio.h>  
#include "hello.h"  

int main(){  
    say_hello();  
    return 0;  
}